This description relates to operation of sensor networks such as those used for security, intrusion and alarm systems installed on commercial or residential premises.
It is common for businesses and homeowners to have a security system for detecting alarm conditions at their premises and signaling the conditions to a monitoring station or to authorized users of the security system. Security systems often include an intrusion detection panel that is electrically or wirelessly connected to a variety of sensors. Those sensors types typically include motion detectors, cameras, and proximity sensors (used to determine whether a door or window has been opened). Typically, such systems receive a very simple signal (electrically open or closed) from one or more of these sensors to indicate that a particular condition being monitored has changed or become unsecure.
Constrained computing devices as used herein are devices with substantially less persistent and volatile memory than other computing devices, sensors, etc. used in a detection system. Currently examples of constrained devices would be those with less than about a megabyte of flash/persistent memory, and less than about 10-20 kbytes of RAM/volatile memory).
Updating firmware on such devices typically involves boot-loading that requires transmission of the entire executable code image over a communications interface even if only a portion of the code changes.